请问最近有走亲属移民的收到I130 approval letter吗？

在给父母办移民，父亲的 I-130刚批了，可是信上说  A visa is not yet available for the beneficiary.Once a visa becomes available, the beneficiary may be eligible to adjust status under section 245(i) of the Immigration and Nationality Act.

现在很糊涂因为觉得immediate family members是不受visa quota限制的，visa number应该时刻都available。他们的I-485也已经在网上交I-130后邮寄到了，receipt也收到了。这种情况正常吗？是USCIS搞错了吗？想问问最近走亲属移民的有没有收到这样的I-130 approval letter。交流一下吧。谢谢

我认为父母不算immediate family，美国对直系亲属的定义是spouse或者21岁以下没结婚的子女。成年子女和父母都自己另算一个household了。

补充内容 (2020-5-10 09:59):
我说错了，应该是说父母和其他类别的直系亲属不是同一个排期

可是USCIS网站上是认父母为直系亲属啊

Green Card for Immediate Relatives of U.S. Citizen
If you are an immediate relative of a U.S. citizen, you can become a lawful permanent resident (get a Green Card) based on your family relationship if you meet certain eligibility requirements.

You are an immediate relative if you are:

The spouse of a U.S. citizen;
The unmarried child under 21 years of age of a U.S. citizen; or
The parent of a U.S. citizen (if the U.S. citizen is 21 years of age or older).

service center 是什么？可以分享一个i130时间线吗？谢谢！